Motor control.



No. 741;796. PATENTED 00120, 1903;. J.D.IHLDER. MOTOR CONTROL.

APPLICATION FILED MAY 5 1902.

N0 MODEL.

V UNITED STATES Patented October 20, 1903.

PATENT OEEIcE.

JOHN D. II-ILDER, OF YONKERS, NElY YORK, ASSIGNOR TO OTIS ELEVATORCOMPANY, OF EAST ORANGE, NEW JERSEY, A CORPORATION OF NEW JERSEY.

MOTOR CONTROL.

SPECIFICATION forming part of Letters Patent No. 741,796, dated October20, 1903.

Application filed May 5, 1902. Serial No. 106,073. (No model.)

To all whom it may concern:

Be it known that I, JOHN D. IHLDER, a citizen of the United States,residing at Yonkers, in the county of Westchester and State of New York,have invented certain new and useful Improvements in Motor Control, ofwhich the following is a specification.

My invention relates to motor control; and its objects are to enableamotor to start with any load and practically unlimited current withoutthe aid of a mechanical dash-pot controlling the starting resistance. Inplace of the usual mechanical dash-pot I provide an electricalequivalent of the same so arranged that the starting resistance is notshort-circuited too rapidly.

Further objects of my invention will hereinafter appear; and to theseends my invention consists of the apparatus and system of control forcarrying out the above objects and having the general mode of operation,substantially as hereinafter fully described, and shown in theaccompanying specification and drawings, in WhlCh- Figure 1 is adiagrammatic representation of an apparatus embodying my invention, andFig. 2 is adiagrammatic view of a modified form of apparatus.

Referring to the drawings, A represents 0 a motor, which may be of anysuitable type,

but shown in this instance as a shunt-wound motor, adapted to beconnected in circuit with the supply-mains (indicated by l and andprovided with a series field-winding B 5 and a shunt-field O, theshunt-field being connected to the mains at the points a and b.

A suitable switch D is arranged to control the admission of current tothe motor-armature, and the throwing of the switch-lever c 0 intocontact with contacts 01 and 6 will first complete the circuit of anelectromagnet E, connected across the mains and controlling contacts finthe main armature-circuit. The energizing of magnet E closes contactsfand 43 completes the circuit to the motor through resistance R and theseries field-winding B. The operation of starting thus far describedapplies as Well to Fig. 2 as to Fig. 1.

Instead of a mechanical dash-pot or other equivalent mechanical meansfor regulating the operation of short-circuiting the starting resistanceR, I provide a series of magnets l 2 3, of which there may be anydesired num-' ber, connected across the line and receiving theline-potential, and these magnets are arranged for a high time constant,taking three or four seconds, for instance, to come up to fullmagnetization. This requires large magnets or additional means foraccomplishing this end, as an additional coil X, having a high timeconstant connected in series with the magnets 1 2 3, which may be termedthe accelerating-magnets. The magnets 1 2 3 in Fig. 1 are wound todifferent strengths, so that magnet 1 operates to attract its armature 5with less current strength than magnet 2 and magnet 2 actuates itsarmature (3 with a current strength less than the magnet 3. Any otherequivalent construction and arrangement of magnets may be provided, sothat the resistance R and series field B will be graduallyshort-circuited as the motor starts, and the armatures 5, 6, and 7 inFig. 1 are actuated and attracted against the cores 7c of magnets 1, 2,and 3.

The time constant of the accelerating-magnets may be made adjustable byproviding an adjustable winding as a shunt to the magnet X or by varyingthe position of the iron core 00 in the coil, as shown by means of thehandle y.

Instead of using large magnets 1, 2, and 3 smaller magnets may be usedand the same time adjustment provided for by operating one magnet afterthe other, thereby adding the time taken to magnetize each magnet, asillustrated in Fig. 2, and this modification may be used with or withoutthe large coil X.

In Fig. 2 as magnet 1 actuates its core 7; to close the circuit betweencontacts 8 12 and 9 13 a portion of the resistance R is short-circuitedand the circuit of the next magnet 2 is closed, and a similar operationis repeated when magnet 2 becomes energized, the circuit of magnets 2and 3 being normally open and closed between contacts 9 13 and 11 15,while armature 7 operates to short-circuit the series winding B.Insulated contacts 10 14: and 8 12 are connected, as shown, toshortcircuit the resistance R.

Contacts (1 and e of switch D are made of different lengths, so that tostop the motor on moving the switch blade e backward circuit withcontact 6 is broken, first throwing the resistance R back into circuit,and then the motor-circuit is broken.

Without limiting myself to the precise construction and arrangement ofparts shown and described, I claim- 1. The combination with a motor, ofelectromagnetic controlling means having a high time constant andconnected to control the motor, substantially as set forth.

2. The combination with a motor, of electromagnetic controlling meanshaving a high time constant and connected to control the motor, andmeans for varying said time constant, substantially as set forth.

3. The combination with a motor and its starting resistance, of magnetshaving a high time constant controlling said resistance and means forvarying said time constant, substantially as set forth.

4:. The combination with a motor and its starting resistance, ofelectromagnetic means having a high time constant controlling saidresistance, and connected to receive the linepotential, and means forvarying said time constant, substantially as set forth.

5. The combination with a motor, of a plurality of magnets connected tocontrol the motor, and means included in the circuit of said magnets forgiving to the same a high time constant, substantially as set forth.

6. The combination with a motor, and its starting resistance, of aplurality of magnets controlling said resistance and connected in seriesacross the line to receive the line-potential, each of said magnetshaving a high time constant, substantially as set forth.

7. The combination with a motor and its starting resistance, of aplurality of magnets controlling said resistance and arranged for a hightime constant, said magnets being connected across the line to receivethe line-potential, substantially as set forth.

8. The combination with a motor and its starting resistance, of aplurality of controlling-magnets arranged for a high time constantconnected across the line to receive the line-potential, and operatingsuccessively, and connections between the magnets such that eachcontrols the circuit of the magnet next to operate, substantially as setforth.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing Witnesses.

JOHN D. IHLDER.

VVituesses:

O. B. MANVILLE, P. W. NEWELL.

